Wednesday, 11 January 2012

Nicolas Steno's 374th Birthday

Google Doodle today (January 11, 2012) come with a theme Nicolas Steno's 374th Birthday.
Who is Nicolas Steno?
Nicolas Steno (Danish: Niels Stensen; Latinized to Nicolaus Steno -gen. Nicolai Stenonis-, Italian Niccolo' Stenone) (11 January 1638 – 25 November 1686) was a Danish pioneer in both anatomy and geology. By 1659 he had decided not to accept anything simply written in a book, resolving instead to do research himself. He is considered the father of geology and stratigraphy. Steno was beatified by Pope John Paul II in 1987.

Steno argued that the chemical composition of fossils could be altered without changing their form.

Steno's work on shark teeth led him to the question of how any solid object could come to be found inside another solid object, such as a rock or a layer of rock.

The "solid bodies within solids" that attracted Steno's interest included not only fossils, as we would define them today, but minerals, crystals, even entire rock layers or strata.

He published his geologic studies in 1669: De solido intra solidum naturaliter contento dissertationis prodromus, or Preliminary discourse to a dissertation on a solid body naturally contained within a solid.

Steno was not the first to identify fossils as being from living organisms. His contemporaries Robert Hooke and John Ray also argued that fossils were the remains of once-living organisms.
Steno wrote about some of the fundamental principles of stratigraphy:

• Superposition: "...at the time when any given stratum was being formed, all the matter resting upon it was fluid, and, therefore, at the time when the lower stratum was being formed, none of the upper strata existed";
• Horizontality: "Strata either perpendicular to the horizon or inclined to the horizon were at one time parallel to the horizon";
• Lateral continuity: "Material forming any stratum were continuous over the surface of the Earth unless some other solid bodies stood in the way";
• Cross-cutting discontinuities: "If a body or discontinuity cuts across a stratum, it must have formed after that stratum".